1. Field of the Invention
This invention relates to data entry devices and systems. More particularly, the invention relates to an improved multiple key station data entry system of the shared processor type.
2. Description of the Prior Art
Data entry systems employing shared processors are known. One well known system employs key stations for entering data directly into a fast access mass memory disk storage system. Areas of the preformatted disk are assigned to individual key stations. Usually, the assigned areas are large enough to accommodate the normal daily work input through each key station; however, the total disk storage capability must be greater than the average configuration or norm expected, consequently, a large portion of the memory disk storage capacity is not utilized. Since some key station operators may be much faster than the norm or average, their assigned area may become filled well before a complete working day. The capacity problem is even worse when a particular job calls for updating data records or making partial entries which results in a greater output of entries in a working day. The more flexible prior art shared processor systems require as a part of the system a tape storage device having standard half inch tape drive and an associated tape controller. This arrangement permits the accumulated data records stored in the mass memory disk storage system to be periodically transferred to magnetic tape. The magnetic tapes may then serve as a temporary or permanent storage record. Most tape storage systems have standard formats for direct entry into a host central processing unit with a minimum of modification, thus become a suitable means for buffer storage.
Prior art shared processor data entry systems have very high initial costs and when employed with a small number of key stations are not economically justifiable. When too many key stations are employed with one mass memory disk file storage system, the access time of the moving head disk file system is too great to accommodate the number of records attempting to be entered randomly per unit of time. It can be shown that head positioning time and random access time of a disk storage system creates a practical limit to the number of key stations that are effectively utilizable with the prior art systems.
Data entry systems employing inexpensive magnetic storage devices with removable diskettes or cartridge tapes have been used in data entry systems and word processors, but such systems have not been employed with shared processors. One well known data entry system provides a key station having a keyboard, a visual display, a diskette drive and a processor for each single or dual station arrangement. The individual processor is limited to only basic programs required to enter data records on the diskette. The data recorded on the diskettes must be physically removed from the key stations and placed in a reader or converter which includes a tape controller, a tape drive and another processor. The records assimilated on such tape are stored for later use as an input to a host central computer. Since the above-described data entry system is intended for off-line operation, the readers or converters are independently free-standing units similar to the key stations. Such prior art data entry systems have very limited format performance. Manual handling of the diskettes and of the resulting tape may require personnel skilled at several different jobs and may require supervisory activities which are not needed on shared processor data entry systems. Key stations having individual diskette systems and processors are not economically competitive with shared processor systems having a large number of key stations.